Move '/docs/SETUP.md' to '/SETUP.md' and '/exercises/TRACK_HINTS.md' …

[jonmcalder]

…- this closes issue #33

[jonmcalder]

I have split these out based on the instructions in #33 and on a cursory look at the xr/go repo which references the testing procedure in the exercises/TRACK_HINTS.md file.

We may want to review the content in each of these two files to make sure it is appropriate given where and how it will appear on the site.

So far I have just replaced "problem.R" and "test_problem.R" with "<exercise_name>.R" and "test_<exercise_name>.R" to highlight that these file names change for each problem.

[petertseng]

Note that if this track (any track) has both SETUP.md and exercises/TRACK_HINTS.md, by https://github.com/exercism/trackler/blob/master/lib/trackler/implementation.rb#L105 only exercises/TRACK_HINTS.md will be used. Since the latter is meant to replace the former, it's one or the other.

[jonmcalder]

Oh ok - I had interpreted your instructions to mean add both not one or the other. Will move everything into exercises/TRACK_HINTS.md then.

Thanks!

[petertseng]

Yup. I recommend that those who have the permission to merge in this repo do so, for the sake of the students completing exercises from this track -- unless there are other problems I didn't see, of course.